Motor-control system



May 12, 1925. 1,537,578

E. M. BOUTON MOTOR CONTROL SYSTEM Filed Sept. 24, 1920 7 J 78 Z IL e9 40 44- r B 46- WITNESSES: INVENTOR Eayarlfl. 50112012 AT' I'ORNEY Patented May 12, 1925.

UNITED STATES PATENT OFFICE.

EDGAR M. BOUTON, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

MOTOR-CONTROL SYSTEM.

Application filed September 24, 1920.

To all whom it may concern:

Be it known that I, EDGAR M. BOUTON, a citizen of the United States, and a resident of lVilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Motor-Control Systems, of which the following is a specification.

My invention relates to motor-control systems and it has particular relation to control systems for efi'ecting the intermittent operation of motors for fixed intervals of time, such, for example, as those employed for driving blowers for pneumatictube devices, whc-h carry packages, cash and the like.

The object of my invention is to provide a control system, for a motor that drives a blower, that will start the motor when a carrier or a package is inserted in a tube and stop the motor after the blower has operated sufiiciently to carry the carrier or package to its destination.

Briefly speaking, my invention consists in providing a control system, for an intermittently operated motor, comprising means for starting a motor when work is about to be begun, afterwards automatically disconnecting the motor from the line by means of a thermal relay, which is set to act at a predetermined time, and. providing an additional relay to permit the thermal relay to reset itself whenever the motor is operated so frequently that, otherwise, there is insufiicient time for the relay to cool.

For a better understanding of my invention, reference should be made to the accompanying drawing consisting of a. single diagrammatic view of a motor-control system embodying my invention.

A blower motor 1, having an armature 2 and a shunt field-magnet winding 3, is electrically energized from line conductors 5 and 6by means of a circuit through aknife switch 7 and a double-pole line contactor 8. A field rheostat 9 is provided for varying the resistance of the circuit including the shunt field-magnet winding 3 of the motor 1.

A plurality of push-buttons 10, 11 and 12 for starting the motor 1 are so constructed that the control system is operated as soon as a carrier 13 is inserted in a pneumatic tube 14, which is supplied with air under Serial No. 412,499.

pressure by the blower motor 1. The pushbutton switches 10, 11 and 12 may be so designed that one of them will be operated by raising a lid or door 15 that is located at the mouth of each of the tubes 14.

A dashpot time-element relay 16 is controlled by the push-button switches 10, 11 and 12 to operate; the auxiliary contactors 17 and 18 by means of a toggle-joint device 19. A thermal relay device 20 and a rheostat 2-1 in series therewith are provided for limiting the time that the motor 1 operates.

The operation of the control system is begun by first closing the knife switch 7 and then inserting a carrier 13 into one of the tubes 14. When the carrier 13 is inserted in the tube 14, it operates the pushbutton switch 10, thereby establishing a circuit from line conductor 5 through knife switch 7, conductors 22 and 26, contact member 23 of the push-button switch 10, conductor 28, actuating coil 29 of the dashpot time-element relay 16, conductors 30, and 33 and the knife switch7 to line conductor 6. The actuating coil 29 of the dashpot time-element relay 16, being energized upon the establishing of this circuit, causes a rod or plunger 27 to rise.

The push-button switch 10 assumes its open position, as soon as the carrier 13 has passed beyond it, or if the push-button switch 10 is controlled by the door 15, as soon as the door is closed.

The rod 27 of the relay with a lower projection or tappet 34 and an upper projection or tappet 35. \Vhen the rod 27 rises, the lower projection 34 strikes a lever 36, which is pivotally mounted on a pin 37. The upper projection 35 strikes the lever 36 when the rod 27 of the relay 16 descends. A counterweight 38, forming part of the lever 36, is so designed as to balance the lever 36 about the pin 37. A depending link or arm 39, forming part of the lever 36, actuates a pivotally mounted toggle-bar 40.

A plurality of contactors 17 and 18 are pivotally mounted near the respective ends of the bar to be controlled thereby. The pin 37 is slidably mounted in a suitable holding member (not shown) that is rovided with a vertical slot. The trave of the pin 37 in this slot is. suflicient to permit the arm 39 of the lever 36 to so actuate the 16 is provided bar 40 that it will efi'ectively operate the contactors 17 and 18. The weight of the lever 36 and counterweight 38 will maintain the particular contactor (17 or 18) that is closed, in that position until the lever 36" is next actuated by the rod 27.

When the arm 36 is raised to its upper position by engaging the projection 34 of the rod 27 of the time-element relay 16, the

contactor 17 is closed thereby establishing a. circuit from line con uctor through knife switch 7 conductors 22, 41 and 42, contact member 31 of the contactor 17, conductors 43and 44, actuating coil 45 of line contactor.

8, conductors 46 and 33 and knife switch 7 to line conductor 6. The actuating coil 45 of the contactor 8 is energized by the completion of this circuit.

When the actuating coil45 is energized, it closes the double-pole line contactor 8,

. thereby establishing a circuit from line concircuit is established.

The shunt field-magnet winding 3 of the motor 1 is energized by its connection through the field rheostat 9 across the armature 2. The motor will thus drive the biotin er (not shown) to supply the necessary air pressure in the tubes 14.

A- holding circuit for the contactor 8-is provided through the auxiliary contact memer 48 thereof and the thermal relay 20 as follows: from line conductor 5 through knife switch 7 conductors 22 and 41, contact members 47 and 48 of the contactor 8, conductors 56 and 57, contact device'58 of the thermal relay 20, conductors 59 and 44, actuatin coil 45 of the contactor 8, conductors 46 an 33 and knife switch 7 to line conductor 6.

When the circuit through the push-button switch 10, which is near the opening of one tube 14, is opened, the actuatlng coil 29 is de-energi'zed, thereb causing the rod 27 of the time-element re ay 16 to descend. The relay 16 is so designed that the rod 27 can be raised rapidly and that it has a time interval of from 5 to 10 seconds in falling. As the rod 27 of the dashpot time-element relay 16 descends to its lower position, the pro ection 35 thereof strikes the lever 36 of the toggle-joint device 18, thereby opening the contact/or 17 and closing the contactor 18.

The opening of the contactor 17 does not sto the motor by permitting the actuating coi 45 of the contactor 8 in become deenergized, since a holding circuit for the contactor 8 is provided through the thermal relay 20, as has already been described. The closing of the contactor 18, however, estabhshes a circuit through the heating coil 60 means of the time-element or thermal relay 20. This circuit is established from line con= ductor 5 through knife switch 7, conductors 22 and. 41, contact members 47 and 48 of contactor 8, conductor 56, heating coil 60, rheostat 21, conductor 63, contact member 32 of contactor 18, conductors 64 and knife switch 7 to line conductor 6.

The current flowing through the heating coil 60 of the thermal relay 20 is controlled by the rheostat 21. By suitably adjusting the rheostat 21, the opening operation of the thermal relay 20 may be made to occur in from 1 to 5 minutes, asconsidered most desirable for the particular system. When the heating coil 60 has caused the enclosed heating element 65 to attain such a temperature that it will open the contact device 58 by actuating the pivotally mounted arm 61, the holding circuit for the actuating coil 45 of the contactor 8 is broken, causing the contactor to open. The time-element relay 20 preferably has its contact device 58 so designed that it operates quickly, to secure effective make and break action. When the contactor 8 is opened, the motor 1 is deener ed.

The dashpot time-element relay 16 has its time of falling adjusted so as to substantially equal the time necessary to permit the heating element 65 of the thermal relay 20 to cool. As has been stated before, this.

period is from 5 to 10 seconds. If, at any time, a carrier 13 is inserted in any tube 14,

and the heating element 65 has just cooled sufliciently to allow the closure of the contactor 58 of the thermal relay 20, the heated condition of the element 65 will not prevent the efi'ective operation of the control system, for the interval of time consumed by the fall of the rod 27 of the dashpot time-element relay 16 will be suflicient to permit the cooling of the complete heating element 65. In other words, if the holding circuit for the contactor 8 is broken by the energization of the coil 60 of the thermal relay 20, and if the contactor 8 is again actuated to its upper position, the relay 20 will have cooled before the circuit comprising the heating coil 60 and contactorS is rev-established.

It will be observed that I have provided a motor-controlsystem for an intermittently operated motor that will ensure the operation of the motor for a predetermined time and the stopping of the motor thereafter regardless of the time intervals between operations, and that apparatus constructed in accordance therewith will be relatively simple and economical in construction and e ective and positive in operation.

'Whi1e I have shown my invention in a preferred form, it is apparent that minor modifications may be made in the apparatus and arrangement of the control circuits without departing from the spirit of the in vention. I desire, therefore, to be limited only by the scope of the appended claims.

I claim as my invention:

1. In a motor-control system, the combination with a motor, of means comprising a thermal relay for operating said motor for a predetermined period of time. and a time element device for rendering said relay inoperative for a predetermined period of time.

2. In a motor-control system. the combination with a motor, of means comprising a time-element relay for operating said motor for a predetermined period, and means comprising a second time-element relay for ensuring effective functioning of said means upon the interval of time between operations becoming greatly diminished.

3. In a motor-control system. the combination with a motor, of means for energizing said motor, a time-element relay for putting said means in operation and for preventing the de-energization of said motor. and a time-limit relay for maintaining said energizing means in operation for a predetermined period.

4.. In a motor-control system, the combination with a. motor, of a cont-actor for energizing-said motor, a relay for closing said contactor, and a time-limit relay for maintaining said contactor closed for a predetermined period after' the operation of said first relay.

5. In amotor-control system, the combination with a motor, of a cont-actor for energizing said motor. a time-limit relay for closing said contactor for a predetermined period.and a thermal relay for maintaining said contactor closed a predetermined interval of time after the operation of said time-limit relay.

6. In a motor-control system. the combination with a motor and a supply source of energy, of means for connecting said motor to said source. means comprising a. thermal relay for automatically disconnecting said motor from said soureigand means comprisinga second relay for permitting said thermal relay time to cool upon the period between operations of said motor becoming brief.

7. In a motor-control system, the combination with a motor and a supply source of energy. of means for connectingsaid motor to said source. means comprising-a timing device for automatically disconnecting said motor from said source, and meauscomprising a second timing device for ensuring a sufiicient interval of time for saidlfirst device to return to its normal condition upon the period between operations of said motor becoming short. y

In testimony whereof, I have hereunto subscribed my name this 14th day of September 1920.

EDGAR M. BOUTON. 

